As a person who works in HFT, I don't really understand the supposed edge of hedge funds. The article makes it sound like the core strategy is buying some stock

As a person who works in HFT, I don't really understand the supposed edge of hedge funds. The article makes it sound like the core strategy is buying some stocks and selling others. Why is this revolutionary though? Selling is just offsetting the buys and reducing overall exposure to the market, equivalent to having bought less in the first place. Then the article mentions "buying in a bull market" and "selling in a bear market" - which obviously makes money, but is predicated on your ability to predict market moves, the possibility of which is highly questionable... And if you already know what the market is doing, then hedging only reduces your upside. It seems to me like the real strategy here is predicting market moves, and everything else is just paper shuffling. If directional investors want to limit their downside, then invest less in the first place. Isn't there some quote from Warren Buffett about simple index fund investment typically beating hedge funds? Hedge funds' attempts at micromanaging risk gets in the way of simple compounding.